The present invention relates generally to structures for cooling the surface defining a duct for conducting a heated fluid, such as the exhaust duct liner of a gas turbine engine.
One of the major difficulties in the design of combustion chambers for ramjet, turbojet and rocket motors exposed to the hot mainstream gas is the severe and uneven heating of gas path surfaces resulting in hot streaks and transverse/longitudinal variations in the radiant and convective heat loads. Cooling system structures for liners must be carefully designed to successfully cool the liners under widely varying heat transfer conditions characteristic of hot engine operation. Efficient use of air film cooling is dependent on the method used to inject air into the hot gas mainstream, i.e., the air must form a continuous cool film over the surfaces where protection from the hot mainstream is desired, and must experience minimum mixing with the mainstream in order to maximize the axial extent of liner cooling.
It is therefore a principal object of the invention to provide structure for cooling a duct carrying a heated fluid.
It is a further object of the invention to provide structure for cooling the exhaust duct of a gas turbine engine.
It is a yet another object of the invention to provide structure for cooling a gas turbine engine exhaust duct liner by the injection of a coolant film of air.
These and other objects of the invention will become apparent as a detailed description of representative embodiments proceeds.